Anti-soil silicone varnish compositions and support substrates treated therewith

ABSTRACT

Silicone compositions, particularly for the production of anti-fouling varnishes which may be applied to flexible or bulk supports to provide an anti-fouling silicone varnish for textiles coated with elastomeric silicones which is economical, adhesive, low-slip and glossy; these are crosslinked silicone compositions comprising: A. at least one alkenylsilane, B. at least one catalytic system which comprises: B/1 at least one organometallic condensation catalyst, B/2 at least one metal M chelate and/or one metal alkoxide of general formula M(OJ) n , wherein n=valence of M and J=linear or branched C 1 -C 8  alkyl radical, M being selected from among: Ti, Zr, Ge and Al, C. at least one ultrafine filler, D. optionally, at least one arylsilane other than A. E. optionally, at least one other silane other than A. and other than D., F. optionally, at least one thickening agent and G. optionally, at least one functional additive.

CROSS-REFERENCE TO PRIORITY/PCT APPLICATIONS

This application claims priority under 35 U.S.C. § 119 of FR 02/16710,filed Dec. 26, 2002, and is a continuation of PCT/FR 2003/003616, filedDec. 8, 2003 and designating the United States (published in the Frenchlanguage on Aug. 12, 2004 as WO 2004/067613 A1; the title and abstractwere also published in English), each hereby expressly incorporated byreference and each assigned to the assignee hereof.

CROSS-REFERENCE TO COMPANION APPLICATION

Our copending application Ser. No. ______ [Attorney Docket No.022702-126], filed concurrently herewith and also assigned to theassignee hereof.

BACKGROUND OF THE INVENTION

1. Technical Field of the Invention

The present invention relates to polymer coatings or varnishes capableof conferring resistance to soiling on supports which may be at least.partially composed of silicone.

The support substrates concerned are various and can, in particular, becomposed:

of flexible supports, in particular fibrous supports, which may or maynot be woven, coated with at least one layer for mechanicalstrengthening or protection based on the coating polymer, for example ofthe silicone elastomer type;

of supports in the massive form made of silicone and/or coated with oneor more silicone layers, for example components made of metal, ofplastic or ceramic (composite components, such as electrical insulators,e.g.,);

or else of polymer or elastomer supports, in particular plastic films,such as, for example, protective packaging films.

The present invention also relates to processes for the application tovarious supports of an anti-soil varnish.

Too, this invention relates to supports coated with such anti-soilvarnishes and in particular flexible supports, such as textile clothsoptionally coated with a layer of silicone elastomer, the anti-soilvarnish being applied to the layer of silicone elastomer, such clothsbeing useful for the manufacture:

1. of architectural textiles (components of textile architecture);

2. or else of flexible supports other than architectural textiles.

As regards the field of application 1., it should be appreciated that,throughout the present account and within the meaning of the presentinvention, the term “architectural textile” means a woven fabric ornonwoven fabric and more generally in the fibrous support intended,after coating, for the preparation:

of shelters, of mobile structures, of textile constructions, ofpartitions, of flexible doors, of tarpaulins, of tents, of stands or ofmarquees;

of furniture, of cladding, of advertising displays, of windbreaks or offilter panels;

of solar protection devices, of ceilings and of blinds.

As regards the field of application 2., it will be appreciated thatthese flexible supports other than architectural textiles can, forexample, be those intended for the manufacture, of in particular:

airbags used for the protection of the occupants of a vehicle,

glass braids (woven glass sheaths for thermal and dielectric protectionfor electrical wires),

conveyor belts, fire barrier fabrics or thermal insulation fabrics,

clothes,

compensators (flexible sealing sleeves for pipe work).

Silicone elastomer coatings on textile supports, due to the intrinsicproperties of silicones, already impart numerous advantages on thecomposites thus formed, namely, inter alia:

flexibility,

mechanical strength,

thermal stability,

release properties,

and longevity.

However, in the field of textile architecture, which constitutes animportant application for the above said composites, other requirementshave been formulated, which are in particular the following:

resistance to soiling substances,

good characteristics with regard to appearance,

especially with respect to the coloring and the gloss,

ability to adhesively bond, to make it possible to easily assemble thecomposites two by two,

low sliding coefficient in order to favor the handling of the composite,

good cohesion of the composite.

These properties can be provided by an appropriate surface coating. Thegeneral problem and the basis of the invention is thus the developmentof a silicone varnish capable of fulfilling this role, in particular asregards the anti-soil properties.

However, before satisfying the requirements relating to the finalapplications targeted for the composite, it is important for thisvarnish to furthermore meet upstream specifications, namely, inparticular:

to be able to be easily spread over a silicone layer, indeed even anonsilicone layer (for example polyvinyl chloride, polyurethane orpolyamide),

to adhere perfectly to this silicone or nonsilicone layer,

and more generally to be easy and economical to employ industrially.

2. Description of Background and/or Related and/or Prior Art

WO-A-00/59992 discloses silicone compositions for use in particular forthe preparation of varnishes which can be applied to supports for whichit is desired to reduce the coefficient of friction. One of thesecompositions comprises at least one polyorganosiloxane A (POS) which canbe crosslinked via crosslinking functional groups (CFGs) by the cationicand/or radical route and an initiator C selected from among oniumborates, wherein it additionally comprises POS D molecules substitutedby secondary functional groups (SFGs) carried by silicon atoms andselected from those comprising at least one alkoxy and/or epoxy and/orcarboxyl unit, and optionally a filler (e.g., silica).

These compositions can additionally comprise fillers and in particularsiliceous fillers, which can, for example, be:

combustion or pyrogenic silicas treated with hexamethyldisilazane orwith octamethylcyclotetrasiloxane (specific surface up to approximately300 m²/g), fumed silicas, ground synthetic or natural fibers (polymers),calcium carbonates, talc, clays, titanium dioxides, and the like.

Such compositions are used as anti-soil varnishes for RTV siliconecoatings of fabrics for air bags, for thermal transfer ribbons or forpackaging films.

Such varnishes are not the most effective in terms of anti-soilproperties and can be improved in terms of sliding coefficient. Inaddition, they require the use of specific silicones which can becrosslinked by cationic routes under UV activation, which leaves amargin for improvement economically and with regard to simplifying themeans employed.

It is thus apparent that the prior art is essentially devoid ofanti-soil varnishes compatible with coatings, in particular siliconeelastomer coatings, for supports, in particular textile supports, andeven less in anti-soil varnishes which meet the above specifications.

SUMMARY OF THE INVENTION

Novel anti-soil varnish compositions for various supports have now beendeveloped, optionally silicone supports, in particular flexible supports(textiles), especially those coated with silicone elastomers, orsupports in the massive form made of silicone elastomer, such varnishcompositions having the quality of having good resistance to soiling, ofbeing economical, of being fully attached to the support and inparticular to the coated elastomer layer and of introducing the desiredlow surface slip, as well as a sufficiently glossy appearance.

Another aspect of the present invention is the provision of an anti-soilvarnish which can be easily applied to various types of supports.

Another aspect of the invention is the provision of an anti-soil varnishwhich can be crosslinked, which is easy to employ and which iseconomical.

Another aspect of the present invention is the provision of a varnishcomposition based on silyl-comprising entities compatible with siliconeelastomers and useful, in particular, in the preparation of anti-soilvarnishes, these compositions having a reasonable price and being simpleto prepare.

Another aspect of the invention is the provision of a process for thesimple and economical varnishing of various silicone-comprising supportsor silicones formed, for example, by woven or nonwoven fibroussubstrates coated with a layer of crosslinked silicone elastomer or bysupports in the massive form at least partially composed of silicone,using anti-soil varnish based on silyl-comprising entities compatiblewith the silicone elastomers.

Another aspect of the invention is the provision of a compositecomprising a support coated with at least one layer of elastomer andcovered with a silicone varnish as defined above, for example a cloth(architectural textile) coated with crosslinked silicone elastomer, withhigh resistance to soiling substances.

Thus, to satisfy the above objectives, the present invention firstfeatures crosslinkable silyl-comprising varnishes having, in particular,anti-soil properties and comprising:

A. at least one alkenylsilane;

B. at least one catalytic system comprising:

-   -   B/1 at least one organometallic condensation catalyst;    -   B/2 at least one metal M chelate and/or one metal alkoxide of        general formula M(OJ)_(n), wherein n=valence of M and J=linear        or branched C₁-C₈ alkyl, M being selected from the group        consisting of: Ti, Zr, Ge and Al;

C. at least one ultrafine filler;

D. optionally, at least one arylsilane other than A;

E. optionally, at least one other silane other than A and than D;

F. optionally, at least one thickening agent;

G. optionally, at least one functional additive.

DETAILED DESCRIPTION OF BEST MODE AND SPECIFIC/PREFERRED EMBODIMENTS OFTHE INVENTION

The silicone varnishes according to the invention are advantageous inthat they make it possible to very greatly increase the resistance tosoiling while having a glossy appearance and a low sliding coefficient.

The mechanical qualities and the usual properties of the supports coatedusing the composition according to the invention are not affected.

In addition, this varnish composition has a stability sufficient for usedelayed with respect to its manufacture by a storage tank compatiblewith marketing criteria.

The combination of components A, B and C, and optionally D and/or Eand/or F and/or G provide exceptional results. This is because it couldnot have been predicted that this combination of carefully selectedcomponents could contribute all of the advantageous results aboveindicated.

The term “alkenyl” means a substituted or unsubstituted, unsaturated,linear or branched, hydrocarbon chain having at least one olefinicdouble bond and more preferably a single double bond. Preferably, the“alkenyl” group has from 2 to 8 carbon atoms, better still from 2 to 6.This hydrocarbon chain optionally comprises at least one heteroatom,such as O, N or S.

Preferred examples of “alkenyl” groups are the vinyl, allyl andhomoallyl groups, vinyl being particularly preferred.

The term “alkyl” denotes an optionally substituted (e.g., by one or morealkyls), saturated, cyclic, linear or branched, hydrocarbon chainpreferably of 1 to 10 carbon atoms, for example of 1 to 8 carbon atoms,better still of 1 to 4 carbon atoms.

Examples of alkyl radicals are in particular methyl, ethyl, isopropyl,n-propyl, tert-butyl, isobutyl, n-butyl, n-pentyl, isoamyl and1,1-dimethylpropyl.

The “alkyl” moiety of the “alkoxy” radical is as defined above.

The “alkyl” can be perfluorinated and the term “perfluorinated alkyl”denotes an alkyl comprising at least one perfluoroalkyl group,preferably having the formula:−(CH₂)_(p)—C_(q)F_(2q+1)in which p represents 0, 1, 2, 3 or 4, q is an integer from 1 to 10 andC_(q)F_(2q+1) is linear or branched. Preferred examples of this radicalare: —(CH₂)₂—(CF₂)₅—CF₃ and —(CF₂)₇—CF₃.

The term “alkylene” denotes an optionally substituted (e.g., by one ormore alkyls), saturated, cyclic, linear or branched, divalenthydrocarbon chain preferably of 1 to 10 carbon atoms, for example of 1to 8 carbon atoms, better still of 1 to 4 carbon atoms.

The expression “aryl” denotes a monocyclic or polycyclic, and preferablymonocyclic or bicyclic, aromatic hydrocarbon group having from 6 to 18carbon atoms. It should be understood that, in the context of theinvention, the term “polycyclic aromatic radical” means a radical havingtwo or more aromatic nuclei fused (ortho-fused or ortho- and peri-fused)to one another, that is to say having, in pairs, at least two carbons incommon.

Mention may be made, as an example of “aryl”, of phenyl radicals.

In accordance with the invention, preferred alkenylsilanes A areselected from the group of products consisting of:

1. the monomers selected from among organoalkenylsilanes comprising, permolecule, at least one alkenyl group, preferably from alkoxylatedorganoalkenylsilanes and more preferably still from the products of thefollowing general formula:

in which:

R¹⁰, R²⁰ and R³⁰ are each hydrogen or hydrocarbon radicals which areidentical or different from one another and preferably representhydrogen, an alkyl or a phenyl radical optionally substituted by atleast one alkyl radical,

L is an alkylene radical,

L₁ is a valency bond or oxygen,

R⁴⁰ and R⁵⁰ are identical or different radicals and are each an alkylradical,

x′=0 or 1,

x=0 to 2, preferably 0 or 1 and more preferably still 0;

2. the oligomers (or condensates) of monomer(s) 1.;

3. the hydrolyzates obtained from monomer(s) 1.;

4. and mixtures thereof.

According to a first preferred characteristic of the invention, themonomers A1. are selected from the subgroup consisting of vinyl- orallylalkoxysilanes and (meth)acryloyloxy(alkoxy)silanes, such asvinyltrialkoxysilanes and methacrylolyoxypropyltrialkoxy-silanes,vinyltrimethoxysilane (VTMO) being particularly appropriate.

According to a second preferred embodiment of the invention, theoligomers (of condensates) A2. are selected from the group consisting ofthose obtained from the monomers A1. and preferably fromvinyltrimethoxysilane (VTMO) or from vinyltriethoxysilane (VTEO).

Mention may be made, as examples of oligomers (or condensates) A2., ofoligomeric vinylsilanes of the type of those sold by Degussa under theregistered trademark Dynasilan® 6490, 6498 or 6598 or else oligomericmethacryloyloxysilanes, such as Dynasilan® 5821 and Dynasilan® 5823.

According to a third preferred embodiment of the invention, thehydrolyzate A3. comprises a mixture of at least one monomer A1. withacidic aqueous solution, the water/alkenylsilane monomer A1. molar ratiobeing less than or equal to 1.5, preferably less than or equal to 1.2,and more preferably still between 0.8 and 1.1.

In practice, the acidification of the medium comprising the hydrolyzateA3. is such that the pH is, for example, between 2 and 4, preferably inthe region of 2.5.

Advantageously, this acidic aqueous solution comprises at least one acidpreferably selected from the acids corresponding to the group consistingof: HCl, H₃PO₄, CH₃COOH and their mixtures.

When it is present, the organometallic condensation catalyst B/1 ispreferably a catalytic tin compound, generally an organotin salt,preferably introduced in the form of an aqueous emulsion. The organotinsalts which can be used are described in particular in the text by Noll,Chemistry and Technology of Silicones, Academic Press, (1968), page 337.

Use may also be made, as catalytic tin compound, either of distannoxanesor of polyorganostannoxanes or of the reaction product of a tin salt, inparticular of a tin dicarboxylate, with ethyl polysilicate, as disclosedin U.S. Pat. No. 3,862,919.

The reaction product of an alkyl silicate or of an alkyltrialkoxysilanewith dibutyltin diacetate, as disclosed in BE-A-842,305, may also besuitable.

According to another possibility, recourse may be had to the tin(II)salt, such as SnCl₂ or stannous octoate.

The preferred tin salts are tin bischelates (EP-A-147,323 andEP-A-235,049), diorganotin dicarboxylates and in particular dibutyl- ordioctyltin diversatates (GB-A-1-289,900), dibutyl- or dioctyltindiacetate, dibutyl- or dioctyltin dilaurates or the hydrolyzis productsof the abovementioned integers (e.g., diorgano- and polystannoxanes).

This catalyst B/1 can also be selected from among the carboxylic acidsalts and the halides of metals other than B/2, such as, for example,lead, zinc, zirconium, titanium, iron, barium, calcium and manganese.

Use is made of 0.01 to 3, preferably of 0.05 to 2, parts of salt B/1 per100 parts of the silanes of the composition.

As regards other component B/2 of the catalytic system B, the preferredproducts are those in which the metal M is selected from the followinglist: Ti, Zr, Ge, Li and Mn. It should be emphasized that titanium ismore particularly preferred. It can be combined, for example, with analkyl radical of butyl type.

The varnishes according to the invention additionally comprise at leastone ultrafine filler C. which may or may not be siliceous.

This ultrafine filler C is selected from inorganic fillers having a meanparticle diameter φme in the region of, preferably less than or equalto, 0.5 μm, advantageously less than or equal to or in the region of 0.1μm; preferably from:

siliceous fillers belonging to the group of silica powders (colloidalsilicas, combustion and precipitated silicas, or their mixtures),

nanometric fillers presented as suspensions, such as, for example,colloidal silica suspensions,

other inorganic fillers selected from the group consisting, inter alia,of: TiO₂, Al₂O₃ (aluminum hydrate) and mica,

or their mixtures.

It may be advantageous to employ, in accordance with the invention, atleast one arylsilane D preferably selected from phenylsilanes and morepreferably still from the group consisting of phenyltrialkoxysilanes,phenylalkyldialkoxysilanes and their mixtures.

According to another advantageous alternative embodiment, the varnishcomposition according to the invention comprises one or more othersilanes E other than the silanes A and D. These silanes E, when they arefunctionalized, comprise, per molecule, one or more functional groupswhich are identical to or different from one another and which areselected from the group consisting of the following functional groups:hydroxyl, amino (primary, secondary or tertiary amine, optionallyincluded in a ring or in isocyanurate groups or HALS groups of thepiperidine or other type), epoxy, (meth)acrylo and ureido.Nonfunctionalized silanes are another option.

Mention may be made, as examples of other silanes E, ofglycidoxypropyltrialkoxysilanes, epoxycyclohexylethyltrialkoxysilanes,aminopropyltrialkoxysilanes, aminoethylaminopropyltrialkoxysilanes,ethyl silicate, methyltrimethoxysilane or methyltriethoxysilane.

The preferred varnish composition is of the type of those which can becrosslinked by polycondensation and comprises:

A. 100 parts by weight of alkenylsilane;

B. 0.1 to 10 parts by weight of a catalytic system including from 0 to80% by weight, preferably from 5 to 60% by weight, of organometalliccondensation catalyst B/1;

C. 2 to 50 parts by weight of ultrafine filler;

D. 0 to 30 parts by weight of at least one arylsilane;

E. 0 to 30 parts by weight of at least one other silane other than A andD;

F. 0 to 5 parts by weight of at least one thickening agent;

G. 0 to 5 parts by weight of at least one functional additive.

The viscosity of the noncrosslinked liquid varnish as applied to thesupport is an important parameter of the invention. Thus, the dynamicviscosity η (expressed in mPa.s at 25° C.) of the A, B and C, optionallyD and/or E and/or F and/or G, varnish is such that:  2 ≦ η ≦ 500preferably  5 ≦ η ≦ 200 and more preferably still 10 ≦ η 23 150.

The dynamic viscosity η at 25° C. can be measured via the well knowntrade test referred to as the Ford cup No. 4 test, which entailsmeasuring the flow time in seconds of a given amount of the productthrough a given orifice. This flow time is converted to a kinematicviscosity in centistokes using a Ford cup calibration curve well knownto one skilled in the art and given in particular in a technical flowcommercial brochure from Byk Gardner, p. 152, which company is asupplier of the Ford cup measuring equipment.

Details with regard to the nature of the various constituents of thesilicone varnish composition according to the invention include: A1. =VTMO; A2. = VTMO oligomers; A3. = VTMO hydrolyzate; B1. = tin salt(e.g., dibutyltin diacetate); B2. = TetraButOxyTitanium (TBOT); C. =treated or untreated pyrogenic silica; D. = phenyltrimethoxysilane; E. =other silane ≠ A ≠ D = for example, ethyl silicate; F. = wax(es) basedon micronized polyamide.

The varnishes according to the invention can comprise functionaladditives G. They can be covering products, such as, for example,pigments/dyes (G.1), stabilizing agents (G.2), in particular with regardto UV radiation, or diluents {solvents} (G.3).

According to an advantageous embodiment of the invention, the varnish isprovided in the form of a single-component system capable of rapidlycrosslinking under hot conditions by polycondensation.

In view of its ease of preparation, its low cost and its anti-soilproperties, the silicone varnishes according to the invention arecapable of having outlets in numerous fields of application and inparticular in the field of the coating:

of supports with a woven or nonwoven fibrous core optionally comprisingsilicone (i.e., coated over at least one of its faces with at least onelayer of elastomer);

or else of supports composed of components in the massive form made ofsilicone and/or comprising silicone.

According to another of its aspects, the invention relates to avarnishing process, wherein the composition as defined above is applied,as anti-soil varnish, to the silicone surface of a support composed atleast in part of silicone, preferably silicone elastomer. It can be asupport at least partially coated with at least one layer of elastomeror a component made of silicone.

According to an alternative embodiment, this varnishing process iscarried out on a support, the surface of which comprises at leastnonsilicone (co)polymer preferably selected from the group consistingof: polyamides, polyolefins, polyesters, their blends and thecopolymers.

Preferably, this process consists essentially:

in coating the support using the varnish composition A, B and C,optionally D and/or E and/or F and/or G, as defined above,

and in crosslinking the layer of varnish, optionally by thermallyactivating the crosslinking.

According to an advantageous embodiment of the invention, the varnishcomposition is applied to the support according to a level of depositionof less than or equal 35 g/m², preferably of between 2 and 25 g/m².

As regards use of the varnish composition according to the invention, itcan, for example, be applied to a support by any appropriate coating ortransfer means (for example, doctor blade, coating roll, gravureprinting, dynamic screen printing, brush, spraying: gun, and the like).

The crosslinking of the varnish liquid silicone composition applied tothe support to be coated is generally activated, for example, by heatingthe surface of the support thus coated to a temperature of between 50and 200° C., taking into account, very clearly, the maximum resistanceof the support to heat.

The activation means are of the type of those known and appropriate forthis purpose, for example thermal activation or activation by IRradiation.

Other details will be given in the examples which follow.

The above defined varnishing process can relate either to architecturaltextiles or to supports other than architectural textiles.

The present invention also features the varnished support (orcomposite), with or without the exception of the composites intended toform architectural textiles as defined above, having anti-soilproperties and a low sliding coefficient which is capable of beingobtained by the process as described above. This composite ischaracterized in that it comprises:

a support, preferably a flexible support, more preferably still selectedfrom the group consisting of:

-   -   textiles,    -   nonwoven fibrous supports,    -   polymer films, in particular polyester, polyamide, polyolefin,        polyurethane, poly(vinyl chloride) or silicone films,

a coating integral with at least one of the faces of the support andcomposed of at least one layer of silicone elastomer and/or of at leastone other (co)polymer,

at least one layer of varnish as defined above.

According to an alternative embodiment, the composite capable of beingobtained by the process described above can comprise:

a support which is massive or block in form optionally made of siliconeand/or at least partially coated with silicone, the silicone preferablybeing a silicone elastomer,

and at least one layer of varnish as defined above.

The silicone coating is optional, for example when the support is itselfsilicone.

Advantageously, the support of the composite according to the inventioncomprises at least one material selected from the group consisting of:

glass, in the massive form or in the form of fibers,

ceramics, in the massive form or in the form of fibers,

natural or synthetic polymers which are provided in the massive form, inthe form of fibers or in the form of films, in particular of polyester,polyamide, polyolefin, polyurethane, poly(vinyl chloride) or silicone,

cellulose or lignocellulose materials in the massive or fibrous form, inparticular paper, board or the like,

and their combinations.

The flexible supports to which the invention relates can be, inter alia,architectural textiles.

Thus, this invention also features an architectural textile, samecomprising a composite capable of being obtained by the varnishingprocess described above and applied to an architectural textile, saidcomposite comprising:

a support, preferably a flexible support, more preferably still selectedfrom the group consisting of:

-   -   textiles,    -   nonwoven fibrous supports,    -   polymer films,

optionally a coating integral with at least one of the faces of thesupport and which comprises at least one layer of silicone elastomer andof at least one other (co)polymer,

at least one layer of varnish as defined above.

Advantageously, the support included in this architectural textilecomprises at least one material selected from the group consisting of:

glass in the form of fibers,

ceramics in the form of fibers,

natural or synthetic polymers which are provided in the form of fibersor in the form of films, in particular of polyester, polyamide,polyurethane, poly(vinyl chloride) or silicone,

cellulose or lignocellulose materials in the massive or fibrous form, inparticular paper, board or the like.

Other flexible supports to which the invention relates and which aredifferent from the “architectural textiles” can be, inter alia, thoseintended for the manufacture of:

airbags used for the protection of the occupants of a vehicle,

glass braids (woven glass sheaths for thermal and dielectric protectionfor electrical wires),

conveyor belts, fire barrier fabrics or thermal insulation fabrics,

clothes,

compensators (flexible sealing sleeves for pipe work), and the like.

According to another of its aspects, the present invention features:

manufactured articles comprising the composite as defined above whichare different from those included in the composition of architecturaltextiles,

and manufactured articles comprising architectural textiles based on thecomposite also defined above.

The fibrous supports intended to be coated and then varnished inaccordance with the invention can, for example, be woven fabrics,nonwoven fabrics or knitted fabrics or more generally any fibroussupport comprising fibers selected from the group of materialsconsisting of: glass, silica, metals, ceramics, silicon carbide, carbon,boron, natural fibers, such as cotton, wool, hemp or flax, artificialfibers, such as viscose, or cellulose fibers, synthetic fibers, such aspolyesters, polyamides, polyacrylics, chlorofibers, polyolefins,synthetic rubbers, poly(vinyl alcohol), aramids, fluorofibers,phenolics, silicones, and the like.

Mention may be made, as preferred examples of fibrous supports, ofglass, polyester, polyamide, polyurethane, polyolefin, poly(vinylchloride) or silicone fabrics or else paper, board or the like.

In addition to textile flexible supports coated with silicone, theanti-soil varnish according to the invention can be applied to plasticfilms (for example, protective packaging films), e.g., made ofpolyester, polyurethane, polyamide, polyolefin (polyethylene,polypropylene), poly(vinyl chloride) or silicone.

The present invention furthermore also features the use of a compositionas defined above as anti-soil varnish on a silicone or nonsiliconesurface, preferably on a silicone surface, for example for coating afibrous support, with or without the exception of any architecturaltextile.

The supports which are massive or block in form to which the inventionrelates can, inter alia, be components selected from the groupconsisting of:

furniture,

cladding,

advertising displays,

windbreaks,

compensators (flexible sealing sleeves for pipework),

or filter panels.

Finally, the present invention features any manufactured articlecomprising the composite as defined above.

The silicone capable of forming the coating or the component which ismassive in form to which the varnish composition according to theinvention is capable of being applied can be an elastomer based onpolyorganosiloxane(s) which can be crosslinked or which is at leastpartially crosslinked and which is preferably selected from:

polyaddition or polycondensation, RTV silicones,

and/or peroxide-cured or polyaddition HCE silicones,

and/or polyaddition LSR silicones.

The anti-soil varnish obtained from the composition as defined above isapplied to the upper layer(s) of silicone elastomer.

The expressions “RTV”, “LSR” and “HCE” are well known to one skilled inthe art: RTV is the abbreviation for “Room Temperature Vulcanizing”, LSRis the abbreviation for “Liquid Silicone Rubber” and HCE is theabbreviation for “Heat Curable Elastomer”.

In practice, the invention more specifically features supports (forexample textiles, such as those used for the manufacture of airbags),coated on one and/or other of their faces with a layer of RTV, HCE orLSR crosslinked silicone elastomer, itself coated with an anti-soilsilicone varnish coating as defined above.

The problem of the introduction of anti-soil properties is particularlyacute regarding these crosslinked silicone elastomer coatings since, ashas already been indicated above, the latter have the characteristic ofhaving a tacky feel.

The polyorganosiloxanes which are the main constituents of the tackylayers of crosslinked elastomers or of the supports/components which aremassive in form on which the varnish according to the invention iscapable of being applied can be linear, branched or crosslinked and cancomprise hydrocarbon radicals and/or reactive groups, such as, forexample, hydroxyl groups, hydrolyzable groups, alkenyl groups andhydrogen atoms. It should be noted that polyorganosiloxane compositionsare fully described in the literature and in particular in the test byWalter Noll: Chemistry and Technology of Silicones, Academic Press,1968, 2nd edition, pages 386 to 409.

More specifically, these polyorganosiloxanes which can be varnished arecomprised of siloxyl units of general formula: $\begin{matrix}{R_{n_{1}}^{{^\circ}}{SiO}_{\frac{4 - n_{1}}{2}}} & \left( I^{\prime} \right)\end{matrix}$and/or of siloxyl units of formula: $\begin{matrix}{Z_{x_{1}}^{{^\circ}}R_{y_{1}}^{{^\circ}}{SiO}_{\frac{4 - x_{1} - y_{1}}{2}}} & \left( {II}^{\prime} \right)\end{matrix}$in which formulae the various symbols have the following meanings:

the R° symbols, which are identical or different, each represent a groupof nonhydrolyzable hydrocarbon nature, it being possible for thisradical to be:

an alkyl or haloalkyl radical having from 1 to 5 carbon atoms andcomprising from 1 to 6 chlorine and/or fluorine atoms,

cycloalkyl and halocycloalkyl radicals having from 3 to 8 carbon atomsand comprising from 1 to 4 chlorine and/or fluorine atoms,

aryl, alkylaryl and haloaryl radicals having from 6 to 8 carbon atomsand comprising from 1 to 4 chlorine and/or fluorine atoms,

cyanoalkyl radicals having from 3 to 4 carbon atoms;

the Z° symbols, which are identical or different, each represent ahydrogen atom, a C₂-C₆ alkenyl group, a hydroxyl group, a hydrolyzableatom or a hydrolyzable group;

n₁=an integer equal to 0, 1, 2 or 3;

x₁=an integer equal to 0, 1, 2 or 3;

y₁=an integer equal to 0, 1 or 2;

the sum x+y is between 1 and 3.

Mention may be made, by way of illustration, among the R° organicradicals directly bonded to the silicon atoms, of the methyl, ethyl,propyl, isopropyl, butyl, isobutyl, n-pentyl, t-butyl, chloromethyl,dichloromethyl, α-chloroethyl, α,β-dichloroethyl, fluoromethyl,difluoromethyl, α,β-difluoroethyl, 3,3,3-trifluoropropyl,trifluorocyclopropyl, 4,4,4-trifluorobutyl,3,3,4,4,5,5-hexafluoropentyl, β-cyanoethyl, γ-cyanopropyl, phenyl,p-chlorophenyl, m-chlorophenyl, 3,5-dichlorophenyl, trichlorophenyl,tetrachlorophenyl, o-, p- or m-tolyl, α,α,α-trifluorotolyl or xylyl,such as 2,3-dimethylphenyl or 3,4-dimethylphenyl, groups.

The R° organic radicals bonded to the silicon atoms are preferablymethyl or phenyl radicals, it being possible for these radicalsoptionally to be halogenated, or else cyanoalkyl radicals.

The Z° symbols can be hydrogen atoms, hydrolyzable atoms, such ashalogen atoms, in particular chlorine atoms, vinyl groups, hydroxylgroups or hydrolyzable groups, such as, for example, amino, amido,aminoxy, oxime, alkoxy, alkenyloxy or acyloxy.

The nature of the polyorganosiloxane and thus the ratios of the siloxylunit (I′) and (II′) to one another and the distribution of the latteris, as is known, selected according to the crosslinking treatment whichwill be carried out on the curable (or vulcanizable) composition for thepurpose of converting it to elastomer.

It is possible to use a great variety of single-component ortwo-component compositions which crosslink by polyaddition orpolycondensation reactions in the presence of a metal catalyst andoptionally of an amine and of a crosslinking agent.

Two-component or single-component polyorganosiloxane compositions whichcrosslink at ambient temperature (RTV) or under hot conditions (HCE) bypolyaddition reactions, essentially by reaction of hydrosilyl groupswith alkenylsilyl groups, in the presence of a metal catalyst,preferably a platinum catalyst, are disclosed, for example, in U.S. Pat.Nos. 3,220,972, 3,284,406, 3,436,366, 3,697,473 and 4,340,709. Thepolyorganosiloxanes participating in these compositions are generallycomposed of pairs based, on the one hand, on a linear, branched orcrosslinked polysiloxane composed of (II′) units in which the Z° residuerepresents a C₂-C₆ alkenyl group and where x₁ is at least equal to 1,optionally in combination with (I′) units, and, on the other hand, on alinear, branched or crosslinked hydropolysiloxane composed of (II′)units in which the Z° residue then represents a hydrogen atom and wherex₁ is at least equal to 1, optionally in combination with (I′) units.

Two-component or single-component polyorganosiloxane compositions whichcrosslink at ambient temperature (RTV) by polycondensation reactionsunder the effect of moisture, generally in the presence of a metalcatalyst, for example a tin compound, are disclosed, for example forsingle-component compositions, in U.S. Pat. Nos. 3,065,194, 3,542,901,3,779,986 and 4,417,042 and in FR-A-2,638,752 and, for two-componentcompositions, in U.S. Pat. Nos. 3,678,002, 3,888,815, 3,933,729 and4,064,096. The polyorganosiloxanes included in these compositions aregenerally linear, branched or crosslinked polysiloxanes comprising (II′)units in which the Z° residue is a hydroxyl group or a hydrolyzable atomor group and where x₁ is at least equal to 1, with the possibility ofhaving at least one Z° residue which is equal to a hydroxyl group or toa hydrolyzable atom or group and at least one Z° residue which is equalto an alkenyl group when x₁ is equal to 2 or 3, said (II′) unitsoptionally being used in combination with (I′) units. Such compositionscan additionally comprise a crosslinking agent which is in particular asilane carrying at least three hydrolyzable groups, such as, forexample, a silicate, an alkyltrialkoxysilane or anaminoalkyltrialkoxysilane.

These RTV organopolysiloxane compositions which crosslink bypolyaddition or polycondensation reactions advantageously have aviscosity at 25° C. at most equal to 100,000 mPa.s and preferably ofbetween 5,000 and 50,000 mPa.s.

It is possible to employ RTV compositions which crosslink at ambienttemperature by polyaddition or polycondensation reactions having aviscosity at 25° C. of greater than 100,000 mPa.s, such as that withinthe range from a value of greater than 100,000 mPa.s to 300,000 mPa.s;this form is recommended when it is desired to prepare filler-comprisingcurable compositions in which the filler(s) used has(have) a tendency toseparate by sedimentation.

It is also possible to employ compositions which crosslink under hotconditions by polyaddition reactions and more specifically polyadditioncompositions said to be of HCE type having a viscosity at 25° C. atleast equal to 500,000 mPa.s and preferably of between 1 million mPa.sand 10 million mPa.s and even more.

The compositions can also be compositions which can be cured at hightemperature under the action of organic peroxides, such as2,4-dichlorobenzoyl peroxide, benzoyl peroxide, t-butyl perbenzoate,cumyl peroxide or di(t-butyl) peroxide. The polyorganosiloxane or gumincluded in such compositions (referred to simply as of HCE type) isthen composed essentially of (I′) siloxyl units, optionally incombination with (II′) units in which the Z° residue represents a C₂-C₆alkenyl group and where x₁ is equal to 1. Such HCEs are disclosed, forexample, in U.S. Pat. Nos. 3,142,655, 3,821,140, 3,836,489 and3,839,266. These compositions advantageously have a viscosity at 25° C.at least equal to 1 million mPa.s and preferably of between 2 millionand 10 million mPa.s and even more.

Other polyorganosiloxane compositions which can be varnished by thesilicone varnish composition according to the invention are those,single-component or two-component, which crosslink under hot conditionsby polyaddition reactions, referred to as LSR compositions. Thesecompositions correspond to the definitions given above with respect tothe preferred compositions referred to as RTV compositions, except asregards the viscosity, which this time is within the range from a valueof greater than 100,000 mPa.s to more than 500,000 mPa.s.

Without this being limiting, the silicone elastomer coatings on whichthe anti-soil varnish according to the invention can be applied are moreespecially coatings obtained from room temperature vulcanizable, RTVsilicone elastomer compositions, in particular of two-component type(RTV 2), by polyaddition.

In order to further illustrate the present invention and the advantagesthereof, the following specific examples are given, it being understoodthat same are intended only as illustrative and in nowise limitative. Insaid examples to follow, all parts and percentages are given by weight,unless otherwise indicated.

EXAMPLES

Tests:

Resistance to Soiling:

Soiling Test:

Carbon black is deposited on the varnish coating and the ability of thesupport to be more or less easily cleaned is recorded on a scale of 0 to5 (cf. single appended figure):

-   -   0=remains black; 5=a few black marks remain

As good wetting is the necessary condition for uniform coating by thevarnish, this covering is assessed by an evaluation of the resistance tosoiling which it introduces.

The resistance is the resistance to the deposition of a carbon blacksoiling substance; the reference chart shown in the single appendedfigure serves for the grading. This figure gives the scale of resistanceto soiling: classification from 0 to 5, from the most to the leastsoiling.

Visual Appearance:

It is recorded whether the varnish confers a glossy or matt appearance.

Support:

1. The support sample is an RTV II coating applied to a polyesterfabric.

This RTV II coating is prepared as follows:

40 kg of an α,ω-divinylated silicone oil with a viscosity of 1.5 Pa.s,which assays 0.1 meq of vinyl (Vi) per gram of oil, 0.24 kg of drinkingwater and 0.24 kg of hexamethyldisilazane are introduced into a 100 larm mixer. After homogenizing, 13.9 kg of a combustion silicacharacterized by a specific surface of 200 m²/g are added portionwiseover approximately 2 hours. After mixing for approximately 1 hour, 2.27kg of hexamethyldisilazane are added over approximately 1 hour. 2 hourslater, a heating phase is begun, during which the mixture is placedunder a stream of nitrogen (30 m³/h); the heating continues untilapproximately 140° C. is reached, which stationary temperature ismaintained for 2 hours in order to remove the volatile materials fromthe composition. The suspension is then allowed to cool.

Starting from this suspension, a part A and a part B are formulated inappropriate reactors.

The part A comprises:

320 g of the suspension,

111 g of an α,ω-divinylated oil with a viscosity of 100 Pa.s whichassays 0.03 meq Vi per gram of oil,

35 g of ground quartz with a mean particle size (d50) of approximately2.5 μm,

12 g of a polyhydro oil with a viscosity of 0.3 Pa.s which assays 1.6meq SiH per gram of oil,

12 g of an α,ω-dihydro oil which assays 1.9 meq SiH per gram of oil,

5 g of γ-methacryloyloxypropyltrimethoxysilane,

5 g of γ-glycidoxypropyltrimethoxysilane,

0.7 g of ethynylcyclohexanol.

The part B comprises:

480 g of the suspension,

20 g of butyl orthotitanate,

1.1 g of a Karstedt catalyst quantitatively determined at 10% ofplatinum.

The parts A and B are mixed in the ratio of 100 to 10 and, after removalof bubbles, the test specimens necessary for the measurement of themechanical properties and of the adhesion properties are prepared.

The crosslinking on the support under consideration is carried out byleaving for 10 minutes in a ventilated oven maintained at 150° C.

The thickness of the coating is sufficient (approximately 300 μm) forthe coated surface to be smooth and for the nature of the fabric used tobecome completely concealed.

2. The varnish is deposited using a Meyer rod; under these conditions,the amount deposited is of the order of 15-20 g/m². The combined productis subsequently introduced into an oven to bring about the drying andthe crosslinking of the varnish.

Example 1

The following compositions are prepared:

Alkenylsilane A.1: Vinyltrimethoxysilane (VTMO),

Alkenylsilane A.2: Dynasilan® 6490 is a vinyltrimethoxysilane (VTMO)condensate sold by Degussa,

Component B.1 of the catalytic system: DBTDA; dibutyltin diacetate,

Component B.2 of the catalytic system: TBOT; butyl titanate,

Ultrafine filler C: R812 is a treated pyrogenic silica sold by Degussa.TABLE 1 Reference 1-1 1-2 1-3 A.1- VTMO 100 — A.2- Dynasilan ® 6490 —100 100 B.1- DBTDA 2 2 2 B.2- TBOT 2 2 2 C- Silica R812 2

The properties evaluated are combined in Table 2 below.

It shows:

the advantage of the condensed silane in terms of gloss,

the reduced reactivity of this silane,

the necessary presence of silica in order to provide the wetting of thesilicone support,

the good resistance to soiling in the case of the varnish 1-3. TABLE 21-1 1-2 1-3 Welling Inadequate Inadequate Correct Time for 1 min 120° C.3 min 120° C. 3 min 120° C. cross linking Appearance Malt Glossy GlossyResistance to 1 1 3 soiling

Example 2:

The following compositions are prepared in a stirred laboratory reactorwith a capacity of 500 cm³ operating at ambient temperature and underenclosed conditions:

Alkenylsilane A.1: Vinyltrimethoxysilane (VTMO),

Alkenylsilane A.2: Dynasilan® 6490 is a vinyltrimethoxysilane (VTMO)condensate sold by Degussa,

Alkenylsilane A.3: hydrolyzate of A.1=A.1+ acid,

Component B.1 of the catalytic system: DBTDA; dibutyltin diacetate,

Component B.2 of the catalytic system: TBOT; butyl titanate,

Ultrafine filler C: R812 is a treated pyrogenic silica sold by Degussa,

Arylsilane D,

Thickening agent F: micronized polyamide C Super® is the CrayVallac®Super distributed by Cray Valley. TABLE 3 Reference 2 A.1- VTMO 27.34A.2- Dynasilan ® 6490 2.66 A.3- Hydrochloric acid, 10⁻²M 10 B.2- TBOT 60B.1- Dibutyltin diacetate 2 C- Silica, R 812 0.2 D-Phenyltrimethoxysilane 1.75 F- Thickening agent, C Super 1

The hydrolyzis of the VTMO A.1 is first carried out by contact with theacid with stirring.

At the same time, the silica C and the thickening agent F C Super, areenergetically dispersed in the alkenylsilane A.2, Dynasilan 6490.

The mixture is subsequently brought to completion.

As in example 1, the varnish 2 is deposited on the RTV II siliconecoating.

The wetting of the support is good.

The viscosity measured is 15 mPa.s under a gradient of 100 s⁻¹.

The crosslinking is effective in 1 minute at 120° C.

The film produced has a glossy to satiny appearance.

The resistance to soiling lies between 3 and 4.

Each patent, patent application, publication and literaturearticle/report cited or indicated herein is hereby expresslyincorporated by reference.

While the invention has been described in terms of various specific andpreferred embodiments, the skilled artisan will appreciate that variousmodifications, substitutions, omissions, and changes may be made withoutdeparting from the spirit thereof. Accordingly, it is intended that thescope of the present invention be limited solely by the scope of thefollowing claims, including equivalents thereof.

1. A silyl-containing varnish composition useful for providing anti-soilcoatings, which comprises: A. at least one alkenylsilane; B. at leastone catalytic system comprising: B/1 at least one organometalliccondensation catalyst; B/2 at least one metal M chelate and/or at leastone metal alkoxide of general formula M(OJ)_(n), wherein n=valence of Mand J=linear or branched C₁-C₈ alkyl radical, M being selected from thegroup consisting of Ti, Zr, Ge and Al; C. at least one ultrafine filler;D. optionally, at least one arylsilane other than A; E. optionally, atleast one other silane other than A and other than D; F. optionally, atleast one thickening agent; and G. optionally, at least one functionaladditive.
 2. The varnish composition as defined by claim 1, saidalkenylsilane A being selected from the group consisting of: 1.organoalkenylsilane monomer(s) comprising, per molecule, at least onealkenyl group;
 2. the oligomers or condensates of said monomer(s) 1.; 3.the hydrolyzates obtained from said monomer(s) 1.; and
 4. mixturesthereof.
 3. The varnish composition as defined by claim 2, saidorganoalkenylsilane monomer(s) comprising alkoxylatedorganoalkenylsilane(s).
 4. The varnish composition as defined by claim2, said organoalkenylsilane monomer(s) having the general formula:

in which: the radicals R¹⁰, R²⁰ and R³⁰, which may be identical ordifferent, are each hydrogen, or a hydrocarbon radical; L is an alkyleneradical; L₁ is a valency bond or oxygen; R⁴⁰ and R⁵⁰, which may beidentical or different, are each an alkyl radical; x′=0 or 1; x=0 to 2.5. The varnish composition as defined by claim 2, said monomers A1.comprising vinyl or allylalkoxysilanes or(meth)acryloyloxy(alkoxy)silanes.
 6. The varnish composition as definedby claim 3, comprising oligomers or condensates A2. obtained fromvinyltrimethoxysilane (VTMO).
 7. The varnish composition as defined byclaim 2, comprising a hydrolyzate A3. which comprises a mixture of atleast one monomer A1. in acidic aqueous solution, thewater/alkenylsilane monomer A1. molar ratio being less than or equal to1.5.
 8. The varnish composition as defined by claim 7, said acidicaqueous solution comprising at least one acid selected from the groupconsisting of HCl, H₃PO₄, CH₃COOH and mixtures thereof.
 9. The varnishcomposition as defined by claim 2, comprising from 20% to 60% by weightof oligomers or condensates A2. of said monomer(s) A1.
 10. The varnishcomposition as defined by claim 1, said at least one ultrafine filler Ccomprising inorganic fillers having a mean particle diameter Φme in theregion of or less than 0.5 μm, and selected from the group consisting ofsiliceous fillers which comprise silica powders, colloidal silicas,combustion and precipitated silicas, or mixtures thereof, suspensions ofnanometric fillers, other inorganic fillers which comprise TiO₂, Al₂O₃mica, and mixtures thereof.
 11. The varnish composition as defined byclaim 1, comprising at least one arylsilane D selected from the groupconsisting of phenyltrialkoxysilanes, phenylalkyldialkoxysilanes andmixtures thereof.
 12. The varnish composition as defined by claim 1,comprising at least one other silane E. selected from the group of thefunctionalized silanes comprising, per molecule, one or more functionalgroups which are identical to or different from one another and whichare selected from the group consisting of the following functionalgroups: hydroxyl, amino (primary, secondary or tertiary amine,optionally included in a ring or in isocyanurate groups or HALS groupsof the piperidine or other type), epoxy, (meth)acrylo and ureido. 13.The varnish composition as defined by claim 1, crosslinkable bypolycondensation and which comprises: A. 100 parts by weight ofalkenylsilane; B. 0.1 to 10 parts by weight of a catalytic systemcomprising up to 80% by weight of organometallic condensation catalystB/1; C. 2 to 50 parts by weight of ultrafine filler; D. 0 to 30 parts byweight of at least one arylsilane; E. 0 to 30 parts by weight of atleast one other silane other than A and D; F. 0 to 3 parts by weight ofat least one thickening agent; G. 0 to 5 parts by weight of at least onefunctional additive.
 14. The varnish composition as defined by claim 1,having a dynamic viscosity η, expressed in mPa.s at 25° C. such that:2≦η≦500.
 15. A process for varnishing a support substrate other than anarchitectural textile, comprising coating an anti-soil varnishcomposition as defined by claim 1 onto a silicone face surface of asupport substrate composed at least in part of a silicone.
 16. A processfor varnishing a support substrate other than an architectural textile,comprising coating an anti-soil varnish composition as defined by claim1 onto a support substrate, the face surface of which comprises at leastone nonsilicone (co)polymer.
 17. The process as defined by claim 16,said at least one nonsilicone (co)polymer comprising a polyamide,polyolefin, polyester, or blend or copolymer thereof.
 18. The process asdefined by claim 15, comprising coating the support substrate with saidvarnish composition and then crosslinking the layer of varnishcomposition, optionally by thermally activating the crosslinking. 19.The process as defined by claim 15, comprising coating said varnishcomposition onto said support substrate in an amount of less than orequal to 35 g/m².
 20. A process for varnishing an architectural textile,comprising coating an anti-soil varnish composition as defined by claim1 onto a silicone surface of a support substrate composed at least inpart of silicone.
 21. A process for varnishing an architectural textile,comprising coating on anti-soil varnish composition as defined by claim1 onto a support substrate, the face surface of which comprises at leastone nonsilicone (co)polymer.
 22. The process as defined by claim 21,said at least one nonsilicone (co)polymer comprising a polyamide,polyolefin, polyester, or blend or copolymer thereof.
 23. The process asdefined by claim 20, comprising coating the support substrate with saidvarnish composition and then crosslinking the layer of varnishcomposition, optionally by thermally activating the crosslinking. 24.The process as defined by claim 20, comprising coating said varnishcomposition onto said support substrate in an amount of less than orequal to 35 g/m².
 25. A composite which comprises a flexible supportsubstrate selected from the group consisting of: textiles, nonwovenfibrous supports, polymer films, optionally, a coating integral with atleast one of the face surfaces of the support substrate and comprisingat least one layer of silicone elastomer and/or of at least one other(co)polymer, and at least one layer of varnish composition as defined byclaim 1, in crosslinked state.
 26. A composite which comprises a bulksupport substrate optionally shaped from silicone and/or at leastpartially coated with silicone, and at least one layer of varnishcomposition as defined by claim 1, in crosslinked state.
 27. Thecomposite as defined by claim 21 or 22, said support substratecomprising at least one material selected from the group consisting of:glass, in the massive form or in the form of fibers, ceramics, in themassive form or in the form of fibers, natural or synthetic polymerswhich are provided in the massive form, in the form of fibers or in theform of films, cellulose or lignocellulose materials in the massive orfibrous form, and combinations thereof.
 28. An architectural textilecomprising a composite of a flexible support substrate selected from thegroup consisting of: textiles, nonwoven fibrous supports, polymer films,optionally, a coating integral with at least one of the face surfaces ofthe support substrate and comprising at least one layer of siliconeelastomer and of at least one other (co)polymer, and at least one layerof varnish composition as defined by claim 1, in crosslinked state. 29.The architectural textile as defined by claim 28, said support substratecomprising at least one material selected from the group consisting of:glass in the form of fibers, ceramics in the form of fibers, natural orsynthetic polymers which are provided in the form of fibers or in theform of films, cellulose or lignocellulose materials in the massive orfibrous form.